Many contemporary automobiles incorporate power steering units which derive energy from a drive belt coupled via a pulley network to the engine drive shaft. The drive belt must be properly tensioned to provide adequate power and prevent belt slippage. This requires that the pump housing be physically urged in a direction which will tension the belt while the pump support housing bracket adjustment nuts and bolts are tightened.
In most installations the power steering pump housing is constructed of relatively thin metal which can be easily damaged if a crow bar or similar tool is used to wedge the unit away from the engine block to create the required drive belt tension. Moving the unit by hand also creates problems since the amount of tension required necessitates that a relatively high force be applied to the unit. This force, in many instances, can not be created simply by pulling the unit with ones hand.